The injection of tritium in the LGPF has indicated the applicability of tritium as tracer, as it has been detected in three wells. Its low recovery, however, could be due to insufficient concentration injected into well 1R8D. It could also indicate that there is significant dispersion or diffusion of tritium within the reservoir, such that its occurrence in other wells could occur at a much later date.

However, if insufficient concentration was injected, there is a possibility that the tritium injected will not find its way out of the reservoir.

The absence of processed historical matching (Fig. 76) in terms of thermal decline in the wells monitored for tracer could indicate that there are other sources of brine/cooler waters that effected a change in the wells. The tracer tests conducted for tritium in LGPF were able to detect the connection between the injector and the production wells monitored.

HTO with an activity of 10 Ci was injected into well 1R8D and tritium was detected at three monitor wells: 2R3D, 214 and 202.

These wells lie directly on the north-east path of the tritium derived from well 1R8D, along the Sambaloran Fault. The other monitor wells, which are situated to the north of the injector, did not manifest any tritium breakthrough one year after injection. The recovery in these wells, however, is only 0.1-0.4%. Near simultaneous NDS tracer test injected into the same well revealed positive breakthroughs, with recoveries slightly higher at 0.1-1.3%. Both tritium and NDS yielded the highest recovery at well 2R3D, the well nearest the injector.

The tracer results showed the hydrological connection between the wells monitored. The very low recovery, however, suggests other possible paths of the fluids from 1R8D. This was not established in the monitoring programme conducted. Nonetheless, the exercise demonstrated that tritium can indeed be utilized as a tracer in a vapour dominated environment. The major consideration here would be the cost of the tritium and the analysis.